How do I set custom theme colors on a template?

I used a template and you can drag premade theme colors onto it but I want to use custom colors for my company. I made the first page the colors I want but can't find how to make it change all pages the same? So How do you set custom theme colors? and will it also change the modile ready one also?
TY

The color boxes for Themes 1, 2 & 3 are on the bottom left of the program window.
If you edit the colors from here, it will carry through the website.

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To elaborate a bit more on Merlin's excellent advice, edit the Theme Colors in the Color Editor. All instances of that color will change accordingly.